Anselm is the most important Christian theologian in the West between Augustine and Thomas Aquinas. His two great accomplishments are his Proslogium (in which he undertakes to show that Reason requires that men should believe in God), and his Cur Deus Homo? (in which he undertakes to show that Divine Love responding to human rebelliousness requires that God should become a man).
He was born in Italy about 1033, and in 1060 he entered the monastery of Bec in Normandy to study under Stephen Lanfranc, whom he succeeded in office, first as prior of Bec, and later as Archbishop of Canterbury.
In 1078 he was elected abbot of Bec. The previous year, he completed a work called the Monologium, in which he argues for the existence of God from the existence of degrees of perfection (Aquinas's Fourth Way is a variation of this argument).
In 1087, while still at Bec, he produced his Proslogium, an outline of his "ontological argument" for the existence of God. Taking as his text the opening of Psalm 14 ("The fool hath said in his heart: There is no God."), Anselm undertakes to show that the fool is contradicting himself—that the concept of God is unique in that anyone who understands what is meant by the question, "Does God exist?" will see that the answer must be "Yes."
The argument has received mixed reviews from the start. Almost at once another theologian, Gaunilon, wrote, "A Reply on Behalf of the Fool." Thomas Aquinas rejected Anselm's argument as inconclusive (and is followed in this by most Roman Catholic writers today). Kant practically made his reputation as a philosopher by explaining in detail what he thought was wrong with Anselm's argument. On the other hand, Leibniz and others have thought it valid. My Plato professor (R E Allen), no friend of Christianity, says of the argument: "It is one of the most exasperating arguments in the history of philosophy. Every time that you think you have finally refuted it, you end up finding something wrong with your refutation." Modern defenders of the argument include Goedel (the writer on mathematical consistency and provability), Hartshorne, and C Anthony Anderson of California. (Anderson is an atheist. I asked him how he reconciled his atheism with his defense of Anselm, and he said, "I am an atheist on faith. Surely you have met theists who believed in God on faith, despite knowing arguments on the other side that they could not really answer.") For an introduction, see the book God And Other Minds, by Alvin Plantinga. For Goedel's version of the argument, and a reply pointing out a flaw in the argument, and for Anderson's restatement of the Goedel's argument in terms that avoid the original flaw, see Anderson's article, "Some Emendations of Goedel's Ontological Proof" (readable online by subscription). Note that this article and the two earlier ones to which it refers all make extensive use of symbolic logical notation, and will be heavy reading for those not accustomed to said notation.
King William II of England had no fondness for the Church, and at the death of Lanfranc he kept the See of Canterbury vacant until he was gravely ill, whereon he promised to let Anselm be made Archbishop. Anselm was made Archbishop (4 December 1093), the King recovered, and the two began to dispute the extent of the King's right to intervene in Church matters. Anselm went into exile in 1097 and remained in Italy for three years until the King died in 1100.
During that time Anselm was instrumental in settling the doubts of the Greek bishops of southern Italy about the doctrine of the Filioque.
He also devoted the time to writing a book known as Cur Deus Homo? (meaning "Why Did God Become Man?"). In it he puts forward the "satisfaction theory" of the Atonement. Man's offence of rebellion against God is one that demands a payment or satisfaction. Fallen man is incapable of making adequate satisfaction, and so God took human nature upon Him, in order that a perfect man might make perfect satisfaction and so restore the human race. The success of his work may be gauged by the fact that many Christians today not only accept his way of explaining the Atonement, but are simply unaware that there is any other way.
The five works Proslogium, Monologium, Gaunilon's Reply, Anselm On Gaunilon (scroll to the bottom), and Cur Deus Homo? are available at the Internet History Sourcebooks Project.
After the death of King William II in 1100, Anselm returned to England at the invitation of the new king Henry I, only to quarrel with Henry about the lawful extent of the king's control over the selection of bishops and abbots (it must be remembered that these officials had civil as well as religious authority). Anselm was again in exile from 1103 to 1106. In 1107 a compromise was reached, and Anselm returned home to Canterbury, where he lived his last few years in peace, dying 21 April 1109.
Typical of Anselm is his reversal of a tendency among English bishops after the Norman Conquest to ignore or downgrade the Anglo-Saxon saints as representatives of the conquered race. Lanfranc had proposed to remove even Dunstan and Alphege from the calendar, the latter on the grounds that he had not died as a martyr for refusing to deny the Christian faith. Anselm argued that, if he was not a martyr to faith, he was a martyr to justice and to charity.
From the Preface to the Proslogion:
I have written the little work that follows... in the role of one who strives to raise his mind to the contemplation of God and one who seeks to understand what he believes.
I acknowledge, Lord, and I give thanks that you have created your image in me, so that I may remember you, think of you, love you. But this image is so obliterated and worn away by wickedness, it is so obscured by the smoke of sins, that it cannot do what it was created to do, unless you renew and reform it. I am not attempting, O Lord, to penetrate your loftiness, for I cannot begin to match my understanding with it, but I desire in some measure to understand your truth, which my heart believes and loves. For I do not seek to undertand in order that I may believe, but I believe in order to understand. For this too I believe, that "unless I believe, I shall not understand." (Isaiah 7:9)
written by James Kiefer
Almighty God, who raised up your servant Anselm to teach the Church of his day to understand its faith in your eternal Being, perfect justice, and saving mercy: Provide your Church in every age with devout and learned scholars and teachers, that we may be able to give a reason for the hope that is in us; through Jesus Christ our Lord, who lives and reigns with you and the Holy Spirit, one God, for ever and ever. Amen.